The Prime Minister cannot answer a simple question on how she would vote in another EU referendum as she is "hamstrung" by the loss of her parliamentary majority and a "divided party of right wing Brexiteers", the SNP's Westminster group leader has claimed.

Ian Blackford argued Theresa May had not been "straightforward" about how she would vote as he challenged her on the issue during Prime Minister's Questions.

Mrs May hit back, responding there is no second EU referendum.

His comments came as Mrs May earlier refused to say she would back Brexit if the referendum on quitting the European Union was held now.

In a move likely to anger Tory Brexiteers, the Prime Minister, who backed Remain, repeatedly side-stepped questions over which camp she would be in during a radio interview yesterday.

Mr Blackford, the MP for Ross, Skye and Lochaber, asked: "If there was another EU referendum now, I know I would vote to Remain. Why hasn't the Prime Minister been straightforward about how she would vote?"

The Prime Minister replied: "There is no second referendum. The people of the UK voted and we will be leaving the EU in March 2019."

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Mr Blackford said: "The Prime Minister can't answer a simple question... The reason the Prime Minister can't answer a simple question is because she's hamstrung by the parliamentary majority and a divided party of right-wing Brexiteers.

"This morning, Chancellor Philip Hammond admitted a cloud of uncertainty is hanging over the UK economy. The SNP is the only party in this House which is united on this issue.

"We know that crashing out of the single market and the customs union will cost 80,000 jobs in Scotland and £2,000 per person.

"Now is the time for leadership. Will the Prime Minister come off the fence and recognise that if we're to save this economy, we need to stay in the single market and the customs union?"

Mrs May said: "Now is the time for the SNP leadership to accept that to save jobs in Scotland they need Scotland to remain part of the UK."

On LBC, Mrs May insisted she was being "open and honest" when she could not give an answer.

Asked if she had changed her mind about how to vote, she replied: "I don't answer hypothetical questions.

"I voted Remain for good reasons at the time, but circumstances move on."

Mrs May said that on citizens' rights "we're very close to agreement", adding "we want EU citizens to stay here in the UK because we value the contribution they're making".

Her comments came after Labour's Karen Buck (Westminster North) asked the Prime Minister about the issue at PMQs.

She said: "In her radio interview yesterday, the Prime Minister was pressed three times on what would be the position of EU nationals in the event of no deal.

"She was unable to answer, suggesting this was a technical issue - but people do not live technical lives, they live in relationships, in jobs and in their children's schools.

"With the clock ticking and the possibility of 'no deal' Brexit looming nearer, can she reassure the 10,000-plus of my constituents who are EU residents exactly what their rights will be if there is no deal?"

Mrs May replied: "We value the contribution that EU citizens have made in this country and we want them to stay, that's why we made citizens' rights one of the key issues, one the early issues that is being discussed in the negotiations that are currently taking place.

"Of course if there is a no deal - and we are working to ensure we get a good deal - if there is no deal, then obviously we will have to have arrangements with other members states about not just EU citizens here, but about UK citizens in those member states, but what we're working for is to get the best deal for the UK.

"On citizens rights' we're very close to agreement, we want EU citizens to stay here in the UK because we value the contribution they're making."